Happy, I'm thinking about this at the moment, too... I don't know anyone who's used prefolds, but I think like the idea, especially for the newborn stage. I'm going to the house of a nappy-supplier who lets you see all the different varieties and get prices, and discuss options, etc, next week. From what i understand, the prefolds can be used later with pocket nappies or as boosters, if you want to, but in the very early days, they are more likely to be made to fit really small babies, which you're likely have have with twins. I thought pre-folds would be much cheaper than that, though - or does that include all the covers as well?